#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using vin=vector<int>;
using vll=vector<long long>;
using vvin=vector<vector<int>>;
using vvll=vector<vector<long long>>;
using vstr=vector<string>;
using vvstr=vector<vector<string>>;
using vch=vector<char>;
using vvch=vector<vector<char>>;
using vbo=vector<bool>;
using vvbo=vector<vector<bool>>;
using vpii=vector<pair<int,int>>;
using pqsin=priority_queue<int,vector<int>,greater<int>>;
#define mp make_pair
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep2(i,s,n) for(int i=(s);i<(int)(n);i++)
#define all(v) v.begin(),v.end()
#define decp(n) cout<<fixed<<setprecision((int)n)
const int inf=1e9+7;
const ll INF=1e18;

int main(){
    int n;cin>>n;
    vin y(n);rep(i,n)cin>>y[i];
    vvin dp(n,vin(10001));
    rep(i,10001)dp[0][i]=abs(i-y[0]);
    rep(i,n-1)rep(j,10001){
        dp[i+1][j]=dp[i][j]+abs(j-y[i+1]);
        if(j>0)dp[i+1][j]=min(dp[i+1][j],dp[i+1][j-1]-abs(j-1-y[i+1])+abs(j-y[i+1]));
    }
    int ans=inf;
    rep(i,10001)ans=min(ans,dp[n-1][i]);
    cout<<ans<<endl;
}